Odd throttle creep?

Hi ArduCopties,

I'm a multi-copter newbie and have (almost) completed my first build (APM2.5 plus various possibly badly chosen HobbyKing parts).

It's all together now and after making it through the new pre-flight checks on ArduCopter 3.0.1 (which had me stuck for a while) I'm now able to get motors to arm/start/etc.

Testing the quad by holding it with motors spinning and moving it around appears to work well (it counters in the correct direction, etc) and the controls do much as I'd expect.

However, when I hold the quad and increase the throttle to minimum, I've noticed that the motors don't stay at a constant speed - instead, they slowly increase speed over maybe a 5 second period and then sit at a much higher speed than they started.

I thought my RC controller was at fault, but if I plug in the APM and look at the PWM levels for the throttle, they definitely don't jump around or do anything unusual.

My only thought is that is it possible that the APM is expecting to see an increase in altitude (except I'm holding on to it) so it continues to edge the throttle up trying to get the quad to lift?

Basically, I'm worried that the first time I try to fly it not holding on it's just going to disappear into the wide-blue-yonder and I'll never see it again :)

Any help most appreciated,


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  • If you lower the throttle after it spins up, do your motors respond immediately?  Same question for raising the throttle?

    It sounds like your ESC's are programmed to use a soft start mode.  This allows the ESC to spin up the motors slowly rather than trying to get to max speed immediately.  This is preferable when you want to be easier on your motors and main gear such as in the case of large rotor helicopters or for a more realistic helicopter idle up.

    You want your ESC's programmed with startup mode to be set to normal or medium and your timing set to medium or high.  We want multicopters to respond very quickly to inputs from the flight controller.

    Hope this helps.

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